I’m confused??

So I’m not supposed to start my period until around the 16-18th and I’m having light bleeding today the 5th. My period have been normal only being a 2-3 difference when my period does come so pretty normal except one month 2 months ago it was 2 weeks late. But I’m really early if this is my period. My ovulation window was this past week according to glow. What do you guys think